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Newbie: Oil temperature gauge not working?

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I've been a 996 owner for 10+ years and have just become the proud owner of a 2009 4s. I went to check the oil level electronically when it was delivered. I started the car and let it warm up. Alas the oil temperature gauge did not move from the bottom of the gauge and despite the coolant temps moving to normal, the on board computer keeps telling me it is waiting for it to warm up.

I assume the computer is waiting for the oil temp but I'm at a loss as to why the temp isn't changing. Had a PPI on the car before purchase without issues so perhaps something got unplugged. Where is the oil temp sensor and where does it plug in? I don't see any obvious disconnected plugs.

Of course may be I need to be more patient, but I figured the oil temp should atleast have started moving by the time the coolant is up to temp.

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Dammad, the first thing I would do is put the car up, drain the oil and measure it. I'm not sure what the 997.2 is, it probably should be somewhere around 8 quarts. Check the manual it will give you the figure. If it is a lot less then you have found your problem. You have two isolated issues, oil level and oil temp. It is highly unlikely that both would fail at the same time. The one issue I can think  of that might affect both would be a real low oil level. The last thing to go is your oil pressure and you certainly do not want to let it go that far.

let us know what happens and do not drive the car until you have figured it out.

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Yes tempting to drain the oil, but based on other articles, the car would raise a dash warning if the oil is below low. Oil pressure moves up to about 4 and then quickly drops to 2 and then eventually down to 1.75. Given the 997.2 has on-demand oil pumps this seems to indicate that the pressure is ok. I had time this evening to get my durametric out to watch the temps. My durametric 6 software shows 3 different Engine Oil temps: Engine Oil Temp, T030_Engine Oil Temp and T100_Engine Oil Temp. The first of the three rises as one would expect. I watched it up to 70C (158F), but the gauge didn't move and the car won't let me read the oil level still. I would have left it longer but didn't have time. 


While I was in there, I noticed two fault codes:

- PDK code 1990. something about positive torque

- Left code C174. Something about convertible top implausible. 


Is there a good place for 997.2 workshop manuals?

Edited by dammad
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  • Admin


 I Think the Oil level sensor is under neath on this new 3.8 DFI Engine.

It is on my Engine at least. Maybe i am wrong.


No, you ( and Loren ) are correct, I was thinking of the M96/97 layout.



Yes, on the 997-2 the sump mounted oil level sender also sends oil temperature.

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I have had the car since new and put all the mileage on it,

I noticed a whistling sound when Engine was warm maybe a month ago and

have read som other threads regarding this (rennlist) and Porsche listened today and

they also Think it is the waterpump. Does not seem very common on this new Engine.

It does not leak any fluid so thats good.

Edited by Boxsters
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P1990 covers a whole range of similar issues


Positive engine torque intervention not possible

Engine torque intervention not possible

SPI error

Software monitoring, reset was triggered by operating system monitoring A

Software monitoring, implausible calculation of engine rpm control intervention

Software monitoring, calculation of Eshift position implausible
Software monitoring B of signal processing unit


Possible fault causes
- Fault in CAN bus
- DME control unit detects engine fault
- PDK control unit faulty
I suggest clearing the code and seeing if it comes back.
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Thanks Loren. You guys are the best!

Alas after checking the connections the gauge does not move. I let it warm to 73c by durametric but nothing. I would have let it go further but something started to slightly squeak so that freaked me out a bit.

What should I check next?

Edited by dammad
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Have you tried if your instrument gauge reads anything if you unplug the oil temp sender when the engine is still ON? Then plug it back in and check again? Also, there got to be some way you can measure the resistance of the sender (with it unplugged) to have a sanity check that the sender itself is working correctly.

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Yes will try a disconnect. I see one oil sensor working through durametric, would be good to check if that is the sump one.

Is Oil temperature necessary for the oil level test to be enabled? The owner's manual says car temp up to 140F (coolant). Perhaps there's an unspoken oil temp requirement too? 200F?

Edited by dammad
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Ok, finally got some time to test with disconnection. Here's a summary of what I know:


- With the sump oil sensor connected

   - no errors on the instrument panel

   - oil pressure looks normal (jumps to about 4 and then immediately drops to 2 and then down to 1.5)

   - Oil temp and Oil level test don't respond on the instrument cluster

   - Through durametric: T_030_Oil_Temp and T_100_Oil_Temp sensors show no value 

   - Through durametric: Oil Temperature shows a value that climbs up to at least 70C


- Without the sump oil sensor connected

   - Warnings on the dashboard within 30 secs of starting. Shows faulty Oil temp and Oil level sensor warnings

   - Otherwise it operates the same as with sensor plugged in

   - Through durametric: T_030_Oil_Temp and T_100_Oil_Temp sensors show no value still

   - Through durametric: Oil Temperature shows a value that climbs still. So I assume this comes from some other sensor. Looking at my car I seem to have a sensor at the top of the engine that JFP initially mentioned, perhaps that is also used for oil temp in the top of the engine


Based on this, should I suspect the oil level/temp sensor in the sump? I'm not sure what T_30_xxx and T_100_xxx sensor readings mean or where they come from but it is odd they show nothing. However, the car shows no fault with the sensor plugged in so I assume it gives the ECU something it thinks is valid. I don't know what the pinout is on the sump sensor, it has three pins. Alternatively, perhaps its the instrument cluster connections. I couldn't find a way to cause the gauge to move through durametric activations to test it. 


Any ideas?

Edited by dammad
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Obviously you have another oil temp sensor that reads the oil temp that Durametric is reading. The oil level you have seems to be the same one that VW and Audi use http://www.niparts.com/MAC/28C1B4/HELLA/6PR008079081.html


It has three pins +ve, -ve, and signal like shown here http://forums.audiworld.com/showthread.php?t=2797528


I think the sensor is at the top of the probe where the correct oil level has to reach before the sensor will register the oil level (and possibly oil temp) reading. So it sounds very possible your oil level is truly low that it doesn't touch the top part of the probe. I would second Mitjostin's reco of draining the oil and measure it.


Other than that, not sure how to troubleshoot the sender nor the instrument cluster. There's instrument cluster test for 996 in Durametric where it cycles all the gauges in full range. So you couldn't find the same for your car?

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Well, according to our experts that sensor reads both level and temp so, it is the only common denominator I can think of other than the wiring which works because the dash responds to your unplugging it and the cluster itself which you really don't want to think about as it goes for 3 grand. There are ways these sensors can fail which might not give you a fault reading. I guess if it happened to me assuming that the sensor is not crazy expensive I would try changing it. Or you could just take it to a Porsche shop.

I use the Mitchell Online shop manual which would be terrible for something like this. It is not user friendly. It is good for things like component location, torque values and simple procedures like taking your wheels off. It is $30 for one year.

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That Audi forum link is very useful. Thanks. Since replacing the sensor would require draining the oil, I'll do a oil dump first to check the levels and if they are good then I'll change the sensor before refilling. I did not see a 997 durametric instrument test, but will check again.

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Maybe I'm all wrong but it seems to me that letting the car idle to reach correct oils temp for a reading is somewhat of a "fool's errand" as it typically takes a good 10 mins while driving for the needle to budge. Why not drive the car a bit and see if your oil temp moves. If the level is too low you'll get a warning anyway. There maybe is nothing wrong.

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I quick note to close the thread. I changed the oil and oil level sensor.. Now the oil reader and oil temp gauge are now working.. As an FYI for others reading this thread: the oil level sensor operates when the oil is above 60C (140F) -- according to workshop manual. In practice it seems the level is not read continuously but periodically so you might get to 61 or 62 first. The T_030_Oil_temp reading in the durametric seems to be the level sensor.

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